A. Rehber Türker

Speciation of Cr(III) and Cr(VI) in water after preconcentration of its 1,5-diphenylcarbazone complex on amberlite XAD-16 resin and determination by FAAS

A simple and sensitive method for the speciation, separation and preconcentration of Cr(VI) and Cr(III) in tap water was developed. Cr(VI) has been separated from Cr(III) and preconcentrated as its 1,5-diphenylcarbazone complex by using a column containing Amberlite XAD-16 resin and determined by FAAS. Total chromium has also been determined by FAAS after conversion of Cr(III) to Cr(VI) by oxidation with KMnO(4). Then, Cr(III) has been calculated by subtracting Cr(VI) from the total. The effect of acidity, amount of adsorbent, eluent type and flow rate of the sample solution on to the preconcentration procedure has been investigated. The retained Cr(VI) complex was eluated with 10 ml of 0.05 mol l(-1) H(2)SO(4) solution in methanol. The recovery of Cr(VI) was 99.7+/-0.7 at 95% confidence level. The highest preconcentration factor was 25 for a 250 ml sample volume. The detection limit of Cr(VI) was found as 45 mug l(-1). The adsorption capacity of the resin was found as 0.4 mg g(-1) for Cr (VI). The effect of interfering ions has also been studied. The proposed method was applied to tap water samples and chromium species have been determined with the relative error <3%.

The use of Agrobacterium tumefacients immobilized on Amberlite XAD-4 as a new biosorbent for the column preconcentration of iron(III), cobalt(II), manganese(II) and chromium(III).

A microorganism Agrobacterium tumefacients as an immobilized cell on a solid support was presented as a new biosorbent for the enrichment of Fe(III), Co(II), Mn(II) and Cr(III) prior to flame atomic absorption spectrometric analysis. Amberlite XAD-4 was used as a support material for column preconcentration. Various parameters such as pH, amount of adsorbent, eluent type and volume, flow rate of sample solution, volume of sample solution and matrix interference effect on the retention of the metal ions have been studied. The optimum pH for the sorption of above mentioned metal ions were about 6, 8, 8 and 6, respectively. The loading capacity of adsorbent for Co(II) and Mn(II) were found to be 29 and 22mumolg(-1), respectively. The recoveries of Fe(III), Co(II), Mn(II) and Cr(III), under the optimum conditions were found to be 99 +/- 3, 99 +/- 2, 98 +/- 3 and 98 +/- 3%, respectively, at the 95% confidence level. The limit of detection was 3.6, 3.0, 2.8 and 3.6ngml(-1) for Fe(III), Co(II), Mn(II) and Cr (III), respectively, by applying a preconcentration factor of 25. The proposed enrichment method was applied for metal ion determination from water samples, alloy samples, infant foods and certified samples such as whey powder (IAEA-155) and aluminum alloy (NBS SRM 85b). The analytes were determined with a relative error lower than 10% in all samples.

Determination of bismuth, indium and lead in geological and sea-water samples by electrothermal atomic absorption spectrometry with nickel-containing chemical modifiers

Abstract The electrothermal atomic absorption spectrometric determination of bismuth, indium and lead in geological samples and synthetic sea water has been carried out by using nickel-containing chemical modifiers. A comprehensive comparison was made among the nickel-containing modifiers such as Ni, Ni+Pd, Ni+Rh, Ni+Pt and Ni+Ru. In addition to that, tartaric acid (TA) was used as a reducing agent together with the above-mentioned mixed modifiers. Comparison was made in terms of pyrolysis temperature, atomization and background absorption signal shapes, and accuracy of the determination. The modifier mixtures of Ni+Pd+TA and Ni+Pt+TA were found to be preferable for the determination of analytes because they increased the pyrolysis temperatures up to 1200–1400°C. Depending on the geological sample type, the percent relative error was decreased from 20.0 to 0.6 for Bi and from 11.9 to 0.4 for Pb by using the proposed modifier systems. The accuracy of the determination of analytes in the synthetic sea water also increased.

Determination of zinc, cadmium, cobalt and nikel by flame atomic absorption spectrometry after preconcentration by poly(ethylene terephthalate) fibers grafted with methacrylic acid☆

Abstract A method for the determination of Zn, Cd, Co and Ni by flame atomic absorption spectrophotometry after preconcentrating on poly(ethylene terephthalate) fibers grafted with methacrylic acid has been developed. The batch adsorption method was used for the preconcentration studies. Effect of pH, amount of adsorbent, concentration and volume of elution solution, shaking time and interfering ions on the recovery of the analytes have been investigated. Recoveries of Zn, Cd, Co and Ni were 97.3±0.4%, 98.3±0.2%, 94.1±0.3% and 96.5±0.6% at 95% confidence level, respectively, at optimum conditions. Langmuir adsorption isotherm curves were also studied for the analytes. The adsorption capacity of the adsorbent was found as 298, 412, 325 and 456 mg/g for Zn, Cd, Co and Ni, respectively. Poly(ethylene terephthalate) fibers grafted with methacrylic acid are suitable for repeated use without loss of capacity for more than thirty cycles. The proposed method was applied to the determination of trace metals in river water and synthetic sea water. Trace metals have been determined with high precision.

Separation and preconcentration of trace manganese from various samples with Amberlyst 36 column and determination by flame atomic absorption spectrometry

This work assesses the potential of a new adsorptive material, Amberlyst 36, for the separation and preconcentration of trace manganese(II) from various media. It is based on the sorption of manganese(II) ions onto a column filled with Amberlyst 36 cation exchange resin, followed by the elution with 5mL of 3mol/L nitric acid and determination by flame atomic absorption spectrometry (FAAS) without interference of the matrix. Different factors including pH of sample solution, sample volume, amount of resin, flow rate of sample solution, volume and concentration of eluent, and matrix effects for preconcentration were investigated. Good relative standard deviation (3%) and high recovery (>95%) at 100mug/L and high enrichment factor (200) and low analytical detection limit (0.245mug/L) were obtained. The adsorption equilibrium was described well by the Langmuir isotherm model with maximum adsorption capacity of 88mg/g of manganese on the resin. The method was applied for the manganese determination by FAAS in tap water, commercial natural drinking water, commercial treated drinking water and commercial tea bag sample. The accuracy of the method is confirmed by analyzing the certified reference material (tea leaves GBW 07605). The results demonstrated good agreement with the certified values.

Separation/Preconcentration of Zn(II), Cu(II), and Cd(II) by Saccharomyces carlsbergensis Immobilized on Silica Gel 60 in Various Samples

Abstract This study presents a solid phase extraction procedure based on column biosorption of Zn(II), Cu(II), and Cd(II) ions on Saccharomyces carlsbergensis immobilized on silica gel 60. The analytes were determined by flame atomic absorption spectrometry (FAAS). The optimum conditions for the quantitative recovery of the analytes, including pH, amount of solid‐phase, eluent type and flow rate of sample solution were examined. The effect of interfering ions on the recovery of the analytes was also investigated. Under the optimum conditions, recoveries of Zn(II), Cu(II), and Cd(II) were 99±2%, 98±2%, and 100±2% at 95% confidence level, respectively for spiked water samples. The analytical detection limits for Zn(II), Cu(II), and Cd(II) were 1.14, 1.66, and 1.48 ng mL−1, respectively. The validation of the method was checked by the analysis of standard reference material (Tea leaves GBW‐07605) and spiked water, samples. The proposed method was applied for the determination of analytes in green onion, parsley, dam water, lake water, and tap water samples. The analytes has been determined in real samples with relative error lower than 8% and relative standard deviation lower than 10%.

Determination of bismuth and lead in geological samples by electrothermal AAS Part 1. Comparative study of tungsten containing chemical modifiers

Abstract A comparative study on the efficiency of some tungsten containing chemical modifiers such as W, W+Pd, W+Rh, W+Pt and W+Ru for thermal stabilization of Bi, In, Pb and Sb has been performed systematically by a Zeeman electrothermal atomization atomic absorption spectrometer (ETAAS). The addition of tartaric acid (TA) as a reducing agent additionally to the mixed modifiers was studied. A mixture of W+Pd+TA was found to be a powerful mixed modifier for the determination of Bi, In, Pb and Sb. Pretreatment temperatures could be increased up to 1250–1500° C using this mixed modifier. The use of the mixed modifier results in an enhanced accuracy and precision of the method and recovery rates above 97% for all samples. The W+Pd+TA mixed modifier was applied to the determination of Bi and Pb in dissolved geological reference samples.

Direct determination of bismuth, indium and lead in sea water by Zeeman ETAAS using molybdenum containing chemical modifiers

Direct determination of Bi, In and Pb in sea water samples has been carried out by ETAAS with Zeeman background correction using molybdenum containing chemical modifiers and tartaric acid as a reducing agent. Maximum pyrolysis temperatures and the effect of mass ratios of the mixed modifier components on analytes have been investigated. Mo+Pd+TA or Mo+Pt+TA mixture was found to be powerful for the determination of 50 mug l(-1) of Bi, In and Pb spiked into synthetic and real sea waters. The accuracy and precision of the determination were thereby enhanced. The recoveries of analytes spiked were 94-103% with Mo+Pd+TA or Mo+Pt+TA and they are only 49-61% without modifier.

Determination of bismuth, indium and lead in spiked sea water by electrothermal atomic absorption spectrometry using tungsten containing chemical modifiers

Abstract The determination of bismuth, indium and lead in spiked synthetic and natural sea water by electrothermal atomic absorption spectrometry (ETAAS) with Zeeman-effect background correction was investigated using tungsten containing chemical modifiers and tartaric acid (TA) as a reducing agent. Maximum pyrolysis and optimum atomization temperatures for the analyte elements were determined in the presence and absence of various modifiers. The lowest detection limits of 8.5, 4, and 1.3 μg l −1 and characteristic mass values of 0.07, 0.04 and 0.02 ng for Bi, In and Pb, respectively, were obtained using the W+Pd+TA mixed modifier, which was found to be most powerful for the determination of Bi, In and Pb spiked into synthetic and natural sea water. The relative error was decreased from 51 to 0.2% for Bi, from 42 to 2% for In and from 51 to 1.2% for Pb by using the proposed W+Pd+TA modifier mixture.

Preconcentration of cobalt using Amberlyst 36 as a solid-phase extractor and its determination in various environmental samples by flame atomic absorption spectrometry

A new and simple column-solid-phase extraction method has been developed to separate and preconcentrate trace cobalt in water and soil prior to its determination by flame atomic absorption spectrometry (FAAS). Different factors such as pH of sample solution, sample volume, amount of resin, flow rate of aqueous solution, volume and concentration of eluent, and matrix effects for preconcentration were optimized. Under optimized experimentally established conditions, an analytical detection limit of 0.44 µg L−1, precision (RSD) of 1.9%, enrichment factor of 200, and capacity of resin of 82 mg g−1 were obtained. The method was applied for cobalt determination by FAAS in tap water, natural drinking water, soil, and roadside dust samples. The accuracy of the method is confirmed by analysing standard reference material (Montana Soil, SRM 2711).